SOLUTION: You go to a local mechanic to get your tires changed. The tires cost $300 each. There is a 6% sales tax, but you get a 10% discount. Write a function, t(x) for the total purch

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: You go to a local mechanic to get your tires changed. The tires cost $300 each. There is a 6% sales tax, but you get a 10% discount. Write a function, t(x) for the total purch      Log On

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Question 1132089: You go to a local mechanic to get your tires changed. The tires cost $300 each. There is a 6% sales tax, but you get a 10% discount.
Write a function, t(x) for the total purchase amount after taxes but before discounts and fees and d(x) to account for the total after discounts on purchase amount x but before taxes and fees. Does it make a difference in the total price if the mechanic adds the tax first or takes the discount first?
I tried different solutions but my teacher keeps saying that they're wrong. Can you please help?
Thanks!

Found 3 solutions by Boreal, Alan3354, josgarithmetic:
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
It does make a difference when you add the tax, and the discount is always taken first, before the tax.
0.90(300x)=270x dollars for x tires. A 10% discount gives the amount discounted; the 90% is what it costs.
The total price is the 270x+(0.06)270x) or 1.06(270x) or f(x)=$286.20x
buy 4 tires and that is 1200 dollars. Ten per cent discount is $120, so the total cost is $1080
6% of $1080 is $64.80, the tax. The final cost is $1144.80
286.20*4=$1144.80

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
How do you get different "solutions?"
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Answer by josgarithmetic(39630) About Me  (Show Source):
You can put this solution on YOUR website!
t(x), total purchase amount after taxes but before discounts and fees
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t%28x%29=300x%2B0.06%2A300x
t%28x%29=10.6%2A300x
highlight%28t%28x%29=318x%29


d(x), the total after discounts on purchase amount x but before taxes and fees.
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d%28x%29=300x-0.10%2A300x
d%28x%29=0.9%2A300x
highlight%28d%28x%29=270x%29


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Does it make a difference in the total price if the mechanic adds the tax first or takes the discount first?
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Think through the question logically.